(x-5)(x+5)=x^2+5x-5x-25=x^2-25
Q=b2/b1=-2/8=-1/4 проверим -2*(-1/4)=1/2 все так.
3.5a²b³a³b⁴c*(-2/7)abc³ = 3.5 * (-2/7) * a²a³a * b³b⁴b * cc³ =<span>-a⁶b⁸c⁴
</span>1) 3.5x³ - 2.5x³ = 0.5x³(7 - 5) = 0.5x³ * 2 = x³
2) 1/7ab + 2/3ab = ab(1/7 + 2/3) = ab(3/21 + 14/21) = ab * 17/21 = (17/21)ab